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1.
Nano-sized zinc oxide (ZnO) is well known for its antibacterial activity and biocompatibility, which make this material a promising candidate to tailor titanium (Ti) implant surfaces. In an optimized scenario, the antibacterial activity of ZnO and its biocompatibility can be envisioned as a good bio-functionalization strategy to increase osteointegration. Thus, in this work, it is proposed that the bio-functionalization of ZnO thin films with dentin matrix protein 1 (DMP1) peptides could function as an apatite crystal nucleator. Ti was coated with ZnO and functionalized with two different spacers, 3-(4-aminophenyl) propionic acid (APPA) or 3-mercaptopropionic acid (MPA) to facilitate binding with DMP1 peptides. Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) results confirmed the presence of the peptides on the ZnO thin film surface through characteristic bands related to amine and carboxylic acid groups and by the incidence of N 1?s spectra, respectively. Atomic force microscopy (AFM) images indicated that a more uniform layer of DMP1 peptides is formed in the the presence of the APPA and MPA spacers. In general, the results obtained showed that the bio-functionalized ZnO thin films with APPA spacer, ZnO APPA P sample, presented enhanced wettability (17°), surface energy (72?dyn/cm), with an osteogenic surface and apatite nucleating properties. Furthermore, the electrochemical analysis showed increased corrosion resistance with noble EOCP (?0.13?V), Ecorr (?0.46?V), and Icorr (8.91?×10?7 A/cm2) values. These findings indicated promising applications of ZnO APPA P in biomedical devices once it can accelerate the osteointegration process and improve the corrosion resistance of implants.  相似文献   

2.
Several ZnO:Al thin films have been successfully deposited on glass substrates at different substrate temperatures by RF (radio frequency) magnetron sputtering method. Effects of the substrate temperatures on the optical and electrical properties of these ZnO:Al thin films were investigated. The UV–VIS–NIR spectra of the ZnO:Al thin films revealed that the average optical transmittances in the visible range are very high, up to 88%. X-ray diffraction results showed that crystallization of these films was improved at higher substrate temperature. The band gaps of ZnO:Al thin films deposited at 25 ℃, 150 ℃, 200 ℃, and 250 ℃ are 3.59 eV, 3.55 eV, 3.53 eV, and 3.48 eV, respectively. The Hall-effect measurement demonstrated that the electrical resistivity of the films decreased with the increase of the substrate temperature and the electrical resistivity reached 1.990×10?3 Ω cm at 250 ℃.  相似文献   

3.
DIPAS (di-isopropylamino silane, H3Si[N(C3H7)2]) and O2 plasma were employed, using plasma-enhanced atomic layer deposition (PEALD), to deposit silicon oxide to function as the gate dielectric at low temperature, i.e., below 200 °C. The superior amorphous SiO2 thin films were deposited through the self-limiting reactions of atomic layer deposition with a deposition rate of 0.135 nm/cycle between 125 and 200 °C. PEALD-based SiO2 thin layer films were applied to amorphous oxide thin film transistors constructed from amorphous In-Ga-Zn-O (IGZO) oxide layers, which functioned as channel layers in the bottom-gated thin film transistor (TFT) structure, with the aim of fabricating transparent electronics. The SiO2 gate dielectric exhibited the highest TFT performance through the fabrication of heavily doped n-type Si substrates, with a saturation mobility of 16.42 cm2/V·s, threshold voltage of 2.95 V and large on/off current ratio of 3.69 × 108. Ultimately, the highly doped Si was combined with the ALD-based SiO2 gate dielectric layers, leading to a saturation mobility of 16.42 cm2/V·s, threshold voltage of 2.95 V, S-slope of 0.1944, and on/off current ratio of 3.69 × 108. Semi-transparent and transparent TFTs were fabricated and provided saturation mobilities of 22.18 and 24.29 cm2/V·s, threshold voltages of 4.18 and 2.17 V, S-slopes of 0.1944 and 0.1945, and on/off current ratios of 9.63 × 108 and 1.03 × 107, respectively.  相似文献   

4.
In this study zirconium incorporated Cr3C2-(NiCr) coating has been sprayed on three superalloys viz. Superni 718, Superni 600 and Superco 605 using D-gun technique. A comparative study has been carried out to check the cyclic oxidation in air and hot corrosion in simulated incinerator environment (40%Na2SO4-40%K2SO4-10%NaCl-10%KCl) for the coated specimens at 900 °C for 100 cycles. Oxidation kinetics has been established for all the specimens using weight change measurements. Corrosion products have been characterized using X-ray diffractometer (XRD) and scanning electron microscopy/energy-dispersive analysis (SEM/EDAX). Cr3C2-(NiCr) + 0.2%wtZr coating provides very good corrosion resistance in air oxidation for all the three coated superalloys. As all the three coated superalloys shows parabolic behaviour with parabolic rate constant as 0.07 × 10?10 (g2 cm?4 s?1) for Superni 718, 0.43 × 10?10 (g2 cm?4 s?1) for Superni 600 and 0.3 × 10?10 (g2 cm?4 s?1) for Superco 605 This coating is also effective in the molten salt environment but coating on Co-based superalloy Superco 605 did not perform satisfactorily. The parabolic rate constants for coated Superni 718 is 0.61 × 10?10 (g2 cm?4 s?1), for coated Superni 600 is 6.72 × 10?10 (g2 cm?4 s?1) and for coated Superco 605 is 17.5 × 10?10 (g2 cm?4 s?1).  相似文献   

5.
Herein, a novel nanocomposite of binary ZnO–CoO nanoparticles loaded on the graphene nanosheets (ZnO–CoO/rGO) has been successfully constructed via a facile, economical and two–step process. The obtained ZnO–CoO/rGO hybrids with high electrical conductivity and abundant active sites, could be modified on a glassy carbon electrode to detect glucose and H2O2 multi–functionally. The fabricated biosensor exhibits wide linear range for glucose (10 μM to 11.205 mM) and H2O2 (25 μM to 11.1 mM), and their corresponding sensitivity are 168.7 μA mM?1 cm?2 and 183.3 μA mM?1 cm?2. The limits of detection are 1.3 μM and 0.44 μM for the oxidation of glucose and the reduction of H2O2, respectively. Furthermore, remarkable selectivity, long–term stability and outstanding reproducibility of the non–enzyme biosensor prove that ZnO–CoO/rGO hybrids are the promising candidate in practical applications.  相似文献   

6.
The ceramic thin films of 47(Ba0.7Ca0.3)TiO3–0.53Ba(Zr0.2Ti0.8)O3 (BCZT) + x (x = 0.2, 0.3, 0.4 and 0.5) mol% Tb were grown on Pt(111)/Si substrates with various annealing temperature by pulsed laser deposition. The XRD spectra confirm that Tb element can enhance the (l10) and (111) orientations in ceramic films. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) images show that Tb-doping can increase particle size effectively. The surface of Tb-doped film annealed at 800 ℃ is uniform and crack-free, and the average particle size and mean square roughness (RMS) are about 280 nm and 4.4 nm, respectively. Comparing with pure BCZT, the residual polarization (Pr) of 0.4 mol% Tb-doped film annealed at 800 ℃ increase from 3.6 to 9.8 μC/cm2. Moreover, the leakage current density value of Tb doped films are one order of magnitude (5.33 × 10?9?1.97 × 10?8 A/cm2 under 100 kV/cm) smaller than those of pure BCZT films (1.02 × 10?7 A/cm2).  相似文献   

7.
The relaxor ferroelectric Pb0.9La0.1(Zr0.52Ti0.48)O3 (PLZT) thin films were deposited using pulsed laser deposition, and their microstructures, break-down field strengths and energy storage performances were investigated as a function of the buffer layer and electrode. A large recoverable energy-storage density (Ureco) of 23.2 J/cm3 and high energy-storage efficiency (η) of 91.6% obtained in the epitaxial PLZT film grown on SrRuO3/SrTiO3/Si are much higher than those in the textured PLZT film (Ureco = 21.9 J/cm3, η = 87.8%) on SrRuO3/Ca2Nb3O10-nanosheet/Si and the polycrystalline PLZT film (Ureco = 17.6 J/cm3, η = 82.6%) on Pt/Ti/SiO2/Si, under the same condition of 1500 kV/cm and 1 kHz, due to the slim polarization loop and significant antiferroelectric-like behavior. Owing to the high break-down strength (BDS) of 2500 kV/cm, a giant Ureco value of 40.2 J/cm3 was obtained for the epitaxial PLZT film, in which Ureco values of 28.4 J/cm3 (at BDS of 2000 kV/cm) and 20.2 J/cm3 (at BDS of 1700 kV/cm), respectively, were obtained in the textured and polycrystalline PLZT films. The excellent fatigue-free properties and high thermal stability were also observed in these films.  相似文献   

8.
The hardness and corrosion resistance of TiN coatings, processed by Electrophoretic Deposition (EPD) to cover polished and unpolished Ti substrates, have been evaluated. A deposition time of 5 min has been enough to obtain a cohesive layer of 7–8 μm in thickness. The coatings were thermally treated in vacuum atmosphere at 1200 °C for 1 h with heating and cooling rates of 5 °C min?1. The surfaces have been covered homogeneously optimizing the properties of the Ti substrates. Uniform and dense TiN coatings have been obtained onto polished substrates, while on unpolished Ti the nitrogen diffuses toward the substrate, moderately dissolving TiN coating. The nanohardness values of the polished samples have been increased from 2.8–4.8 GPa up to 6.5–8.5 GPa. Besides, the corrosion current density has been reduced more than one order of magnitude obtaining a protective efficiency of 82%. These values have been compared with other works in literature where authors used complex and costly processing techniques, demonstrating the strong impact of the colloidal processing over the specific properties of the material.  相似文献   

9.
[0.9(0.94Na0.5Bi0.5TiO3?0.06BaTiO3)?0.1NaNbO3]-xZnO (NBT-BT-NN-xZnO, x=0, 0.5 wt%, 1.0 wt%, 1.5 wt%, and 2.0 wt%) ferroelectric ceramics were fabricated using a conventional solid-state reaction method. The effects of ZnO content on dielectric, energy-storage and discharge properties were systematically investigated. Dielectric constant and difference between maximum and remanent polarization were significantly improved by ZnO doping. Dielectric constant of NBT-BT-NN-1.0-wt% ZnO was 3218 at 1 kHz and room temperature, i.e. one time bigger than that of pure NBT-BT-NN ceramic. As a consequence, a maximum energy-storage density of 1.27 J/cm3 with a corresponding efficiency of 67% was obtained in NBT-BT-NN-1.0-wt% ZnO ceramic. Moreover, its pulsed discharge energy density was 1.17 J/cm3, and 90% of which could be released in less than 300 ns. Therefore, ZnO doped NBT-BT-NN ceramic with a large energy-storage density and short release time could be a potential candidate for applications in high energy-storage capacitors.  相似文献   

10.
High-quality polycrystalline ZnO thin films were deposited onto alkali-free glasses at a temperature of 300°C in air ambience by combining sol–gel spin coating and KrF excimer laser annealing. The effects of laser irradiation energy density on the crystallization, microstructure, surface morphology, and optical transmittance of as-prepared ZnO thin films were investigated and compared to the results of thermally annealed ZnO thin films. The crystallinity level and average crystallite size of laser annealed ZnO thin films increased as laser energy density increased. The crystallinity levels and average crystallite size of excimer laser annealed (ELA) thin films were greater than those of the thermally annealed (TA) thin films. However, laser annealed thin films had abnormal grain growth when irradiation energy density was 175 mJ/cm2. Experimental results indicated that the optimum irradiation energy density for excimer laser annealing of ZnO sol–gel films was 150 mJ/cm2. The ELA 150 thin films had a dense microstructure, an RMS roughness value of 5.30 nm, and an optical band gap of 3.38 eV, close to the band gap of a ZnO crystal (3.4 eV).  相似文献   

11.
Transparent conductive NiO thin films with 18 at% Cu dopant were fabricated by ion beam assisted deposition (IBAD). Their structural and optoelectronic properties were compared with undoped NiO films and NiO films doped with 12 at% Cu, and also compared with NiO:Cu (18 at%) films deposited by RF sputtering as reported in our previous work. The results show that the crystallinity of NiO thin films deposited through IBAD technology is much better than that of the films deposited by RF sputtering. Thanks to this reason, the highest carrier mobility above 45 cm2V?1s?1 for NiO:Cu (18 at%) film can be realized here. Meanwhile, the films’ resistivity remains an acceptable value, varying from 2.05 to 0.064 Ω cm with oxygen ion beam current changing from 0.2 to 0.8 A. This feature is imperative for p-type transparent conductive oxides (TCOs) applied in various domains. In addition, with oxygen ion beam current increase, the increase of the Ni3+/Ni2+ ratio leads to more Ni2+ vacancies be introduced into NiO films, which is beneficial to generate holes and improve carrier concentration. In this work, the optimal carrier mobility of NiO film doped with 18 at% Cu is obtained when the oxygen ion beam current is 0.2 A. Its carrier concentration and electrical resistivity are 7.26 ×1016 cm?3 and 2.05 Ω cm, respectively.  相似文献   

12.
Nanocomposites electrolytes consisting of La3+ and Zr4+ doped with ceria labelled as La0.2 Ce0.8 O2-δ (LDC), Zr0.2Ce0.8O2-δ (ZDC) and Zr0.2La0.2Ce0.6O2-δ (ZLDC) have been synthesized via a co-precipitation route. DC conductivity was studied with a four-probe method in the range of temperature 450–650 °C and maximum conductivity was found to be 0.81 × 10?2 S.cm?1 (LDC) > 0.32 × 10?2 S.cm?1 (ZLDC) > 0.15 × 10?2 S.cm?1 (ZDC) at a temperature of 650 °C, respectively. Further, electric behavior of doped and co-doped ceria electrolytes was investigated by A.C electrochemical impedance spectroscopy (frequency range ~ 0.1 Hz?4 MHz). The phase/structural identification of the material prepared was studied using X-ray diffraction and found ceria to possess a cubic fluorite structure. Scanning electron microscopy (SEM) was carried out to study its morphology and particle size (~ 90–120 nm). Thermal behavior on its change in weight and length with the temperature were studied by thermogravimetric analysis (TGA) and dilatometry respectively. Furthermore, thermal expansion coefficients (TECs) of prepared electrolytes are calculated and found as follows: 13.4 × 10?6 °C?1, 13.6 × 10?6 °C?1and 15.3 × 10?6 °C?1 for LDC, ZDC and ZLDC, respectively, in the temperature range 150–1150 °C.  相似文献   

13.
Using a pulsed laser deposition method the BaZr0.2Ti0.8 O3 (BTZ) lead–free thin films with a thickness of ~250 nm were grown on FTO, ITO and Pt–Si substrates, respectively. The analysis results of microstructural, dielectric properties and leakage current reveal that the thin films deposited on Pt–Si substrates are oriented growth along the (1 1 0) direction and exhibit the optimal performance characteristics. Calculations of figure of merit (FoM) and dielectric tunability display a maximum value of ~42.8 and ~68.5% at E = 400 kV/cm at room temperature, respectively. The excellent tunable properties, high dielectric constant (~635@ 100 kHz) and low leakage current density of (9.3 × 10–8 A/cm2 at 400 kV/cm) make the (1 1 0)–oriented BaZr0.2Ti0.8 O3 thin film to be an attractive material for applications of tunable devices.  相似文献   

14.
In current study, Ni–AlN nanocoatings were successfully prepared by adopting the jet pulse electrodeposition (JPE) technique with ultrasound. The scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Vickers microhardness test, electrochemical workstation and friction wear tests were utilized to investigate the microstructure, mechanical properties, corrosion degree and wear resistance of the coatings. The results indicated that the Ni–AlN nanocoatings deposited by using ultrasound demonstrated the minimum and most compact surface structure compared to the other coatings. The thicknesses of Ni coating and Ni–AlN nanocoatings were approximately 56 µm. The average atomic percent of Al and Ni elements in the Ni–AlN nano-coating prepared by using ultrasound, were approximately 21.4 at% and 47.5 at%, respectively. The maximum kinetic energy of the jet plating solution was 916 m2/s2 during JPE-deposited Ni-AlN nanocoatings including ultrasound. The average micro-hardness value of the nano-coating prepared by using ultrasound equaled 767.9 HV. The Ni–AlN nanocoatings prepared using ultrasound had the minimum Ecorr and Icorr values of ? 0.167 V and 6.363 × 10?6 mA/cm2, respectively. In this case, the demonstrated corrosion resistance was the most efficient. The Ni–AlN nanocoatings prepared using ultrasound sustained the minimum friction coefficients and the average friction coefficient was approximately 0.52. In contrast, the JPE-deposited Ni coating presented the maximum friction coefficient, while the average friction coefficient was approximately 1.43.  相似文献   

15.
《Ceramics International》2016,42(9):10793-10800
Plasma nitriding and plasma-assisted PVD duplex treatment was adopted to improve the load-bearing capacity, fatigue resistance and adhesion of the AlTiN coating. Ion etch-cleaning was applied for better adhesion before plasma nitriding. After plasma nitriding Ti interlayer was in-situ deposited by high power impulse magnetron sputtering (HIPIMS), followed by the AlTiN coating through in-situ deposition by advanced plasma-assisted arc (APA-Arc). The microstructure and properties of the duplex-treated coating were carefully characterized and analyzed. The results show that the thicknesses of the nitriding zone, the γ′-Fe4N compound layer, the Ti interlayer and the AlTiN top layer with nanocrystalline microstructures are about 60 μm, 2–3 μm, 100 nm and 6.1 μm, respectively. The nitriding rate is about 30 μm/h and the AlTiN coating deposition rate reaches 6.1 μm/h. The interfacial adhesion of the Ti/AlTiN coating is well enhanced by ion etch-cleaning and a Ti interlayer, and the load-bearing capacity is also improved by duplex treatment. In addition, the instinct hardness of the Ti/AlTiN coating reaches 3368HV0.05 while the wear rate coefficient of 5.394×10−8 mm−3/Nm is sufficiently low. The Ti/AlTiN coating, which possesses a high corrosion potential (Ecorr=−104.6 mV) and a low corrosion current density (icorr=4.769 μA/cm2), shows highly protective efficiency to the substrate.  相似文献   

16.
By following a one-step, novel methodology, ZnO and Ag/ZnO heterostructures were successfully synthesized at room-temperature. This route is simple, effective, high yield (91%), environmentally friendly (green synthesis) and consists of a mechanically assisted metathesis reaction. The metathesis reaction used in this investigation showed two results: the in-situ generation of alkaline nitrates, LiNO3/NaNO3, and the direct crystallization of the desired Zn-based compounds in milling media; revealing a true mechanochemical synthesis of ZnO and Ag/ZnO (1.25, 2.50 and 4.50 mol% of Ag) heterostructures. Particles showed spherical-like morphologies and sizes smaller than 20 nm. The Ag/ZnO heterostructures exhibited higher photocatalytic activity than ZnO for degrading methylene blue (MB) dye. It was also shown that the presence of Ag (up to 1.25 mol%) nanoparticles (NPs) in ZnO accelerates the photodegradation reaction and then slows down with further increases in Ag contents. The 1.25-Ag/ZnO sample (10 mg) showed the highest photocatalytic activity (96%) for degrading MB (100 ml, 10 mg L?1) within 100 min under UV–Vis light irradiation (λ = 310 nm).  相似文献   

17.
Li2S is coated with carbon to improve the electrical conductivity of the composite cathode in all-solid-state lithium-sulfur batteries. Carbon is applied by thermal evaporation from a polyacrylonitrile (PAN) source at 600 °C for 5 h. It is shown that the carbon coating is impurity free, and the crystallinity of Li2S is well maintained. The electronic conductivity of Li2S is dramatically improved from 9.21 × 10?9 S cm?1 to 2.39 × 10?2 S cm?1 upon carbon coating. An all-solid-state battery prepared with the carbon-coated Li2S shows a high initial capacity of 585 mAh g?1 (g of Li2S) that increases up to 730 mAh g?1 (g of carbon-coated Li2S) by the 10th cycle. This high capacity is stable throughout the 25 cycles tested, with an excellent coulombic efficiency of 99%. Carbon-coated Li2S is advantageous for all-solid-state batteries due to the increased electrical conductivity, while allowing a reduction of the total carbon content present in the composite cathode.  相似文献   

18.
Cu foils of 2 × 2 cm2 have been implanted with 70 keV C ions to nominal fluences of (2–10) × 1015 cm−2 at room temperature (RT) and subsequently annealed at 900–1100 °C for 15 min, before being cooled to RT to form graphene layers on the Cu surfaces. Analyses with Raman spectroscopy and atomic force microscopy demonstrate that a continuous film of bi-layer graphene (BG) is produced for implant fluences as low as 2 × 1015 cm−2, much less than the carbon content of the BG films. This suggests that the implanted carbon facilitates the nucleation and growth of graphene, with additional carbon supplied by the Cu substrate (0.515 ppm carbon content). No graphene was observed on unimplanted Cu foils subjected to the same thermal treatment. This implantation method provides a novel technique for the selective growth of graphene on Cu surfaces.  相似文献   

19.
Further improving electromechanical properties and overcoming relatively low Curie temperature (Tc) of (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-100xPT) are still two scientific issues. Here, we demonstrate a stable coexistence of monoclinic-tetragonal (MC-T) phases in ZnO-modified PMN-32PT (PMN-32PT:xZnO) due to the diffusion-induced substitution of Zn2+ for Mg2+. The Curie temperature, saturated polarization, remnant polarization, piezoelectric coefficient (Tc, Ps, Pr, d33) are increased from (160 °C, 22.0 μC/cm2, 13.3 μC/cm2, 350 pC/N) for x = 0 to (180 °C, 30.3 μC/cm2, 22.4 μC/cm2, 470 pC/N) for x = 0.06. Moreover, the thermal stability is improved. After annealing at 150 °C, the x = 0.06 sample shows retrained d33 value of 209 pC/N, about 4 times larger than that of x = 0 counterpart. The improved properties are attributed to the substituting increased polar nanoregions and easy domain switching in MC phase.  相似文献   

20.
In situ nanostructured (TiCr)CN composite coating was prepared by reactive plasma spraying Ti-Cr-graphite powder under air atmosphere. The phase composition, microstructure, mechanical properties and wear performance were investigated. The results show that the coating consists of a mixture of TiN, Ti(CN), (TiCr)N, Cr, Ti3O, and amorphous graphite and CrN phases. The grain size is about 70 nm and the grains present equiaxed and columnar crystal morphologies. Moreover, 5 nm-sized nanocrystals are embedded in an amorphous phase. The (TiCr)CN composite coating possesses high hardness (1325 ± 120 HV) and toughness (4.35 ± 0.53 MPa m1/2). The friction coefficient and wear rate of the coating are 0.46 and 3.01 ± 0.17 × 10?6 mm3 N?1 m?1, respectively. The inclusion of metallic phase Cr could improve the toughness and wear resistance of the (TiCr)CN coating.  相似文献   

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